diff --git a/mail/inc/class.mail_ui.inc.php b/mail/inc/class.mail_ui.inc.php
index 84fd6ceb02..3c7e5ac7df 100644
--- a/mail/inc/class.mail_ui.inc.php
+++ b/mail/inc/class.mail_ui.inc.php
@@ -2792,13 +2792,13 @@ $filter['before']= date("d-M-Y", $cutoffdate2);
 		{
 			$headers = Horde_Mime_Headers::parseHeaders($message);
 			$subject = str_replace('$$','__',Mail::decode_header($headers['SUBJECT']));
-			$subject = mail_bo::clean_subject_for_filename($subject);
+			$subject = Api\Mail::clean_subject_for_filename($subject);
 			Api\Header\Content::safe($message, $subject.".eml", $mime='message/rfc822', $size=0, true, true);
 			echo $message;
 		}
 		else
 		{
-			$subject = mail_bo::clean_subject_for_filename($subject);
+			$subject = Api\Mail::clean_subject_for_filename($subject);
 			Api\Header\Content::safe($message, $subject.".eml", $mime='text/html', $size=0, true, false);
 			print '<pre>'. htmlspecialchars($message, ENT_NOQUOTES|ENT_SUBSTITUTE, 'utf-8') .'</pre>';
 		}
@@ -2882,11 +2882,11 @@ $filter['before']= date("d-M-Y", $cutoffdate2);
 			if (Vfs::is_dir($path))
 			{
 				$headers = $this->mail_bo->getMessageHeader($uid,$partID,true,false,$mailbox);
-				$file = $dir . '/'.mail_bo::clean_subject_for_filename($headers['SUBJECT']).'.eml';
+				$file = $dir . '/'.Api\Mail::clean_subject_for_filename($headers['SUBJECT']).'.eml';
 			}
 			else
 			{
-				$file = $dir . '/' . mail_bo::clean_subject_for_filename(str_replace($dir.'/', '', $path));
+				$file = $dir . '/' . Api\Mail::clean_subject_for_filename(str_replace($dir.'/', '', $path));
 			}
 
 			if ($savemode != 'overwrite')
@@ -2958,7 +2958,7 @@ $filter['before']= date("d-M-Y", $cutoffdate2);
 		{
 			$dir = Vfs::dirname($path);
 			// Need to deal with any ? here, or basename will truncate
-			$filename = mail_bo::clean_subject_for_filename(str_replace('?','_',Vfs::basename($path)));
+			$filename = Api\Mail::clean_subject_for_filename(str_replace('?','_',Vfs::basename($path)));
 		}
 
 		if (!Vfs::is_writable($dir))
@@ -3155,7 +3155,7 @@ $filter['before']= date("d-M-Y", $cutoffdate2);
 					pathinfo($file['filename'], PATHINFO_EXTENSION);
 			}
 			// Strip special characters to make sure the files are visible for all OS (windows has issues)
-			$target_name = mail_bo::clean_subject_for_filename(iconv($file['charset'] ? $file['charset'] : $GLOBALS['egw_info']['server']['system_charset'], 'ASCII//IGNORE', $file['filename']));
+			$target_name = Api\Mail::clean_subject_for_filename(iconv($file['charset'] ? $file['charset'] : $GLOBALS['egw_info']['server']['system_charset'], 'ASCII//IGNORE', $file['filename']));
 
 			if (!($fp = Vfs::fopen($path.$target_name,'wb')) ||
 				!(!fseek($attachment['attachment'], 0, SEEK_SET) && stream_copy_to_stream($attachment['attachment'], $fp)))